The hardening of magnetic tapes and disks is an important consideration with respect to the durability of such materials when used with various tape and disk drives and magnetic recording heads. The hardening process that is used in virtually all magnetic tapes and disks containing a polyurethane medium is based on the reaction of isocyanate (--NCO) groups and hydroxyl (--OH) groups to form urethane (--NHCOO--) bonds.
The hardness of magnetic tapes and disks that can be achieved by such hardening process is generally less than desired. Inadequate hardness can cause excessive medium wear rate and degrade magnetic performance. It would be highly desirable to provide a simple method to increase the hardness of magnetic disks and tapes.